Prepare your pie crust or use a premade shell. It should be in the pie plate ready to go.
Preheat oven to 375 degrees
In a large bowl, combine the pumpkin filling with the sugar.
Microwave the molasses for about 30 seconds to get it a bit more runny, and less thick. Combine with the pumpkin mixture.
Add in the yolks of the 4 eggs, mixing well. If you've heated the molasses too much you might need to temper the eggs into the mixture when adding.
Add all the spices into the pumpkin puree mixture.
In a seperate bowl, fluff the egg whites with a mixer until light and airy. You want to beat past soft peaks, to stiff peaks.
Fold in the egg whites until the mixture is just combined. Try not to lose the air in the egg whites.
Place on a middle rack and back for approximately 40 mins, checking for doneness.